It is known to provide illuminated signs comprising a rectangular housing containing a light source typically in the form of one or more fluorescent tube units and provided with one or two sign faces which are illuminated by the lights in the sign. The sign faces may be in the form of a single, translucent sheet, painted or marked as desired, or the sign face may be divided into a number of horizontal rows to receive interchangeable panels bearing alphanumeric characters or other symbols. The panels are formed of blocks or panels of transparent material and the characters may be defined by providing, on the face of the panel, a transparent portion defined by an opaque coating. Thus, with the light from the interior of the housing, behind the panel, the transparent portion is highly visible.
One of the problems associated with the use of such reverse type letter panels is of light transmission from between adjacent panels. One method of overcoming this problem is disclosed in Canadian Patent No 1,252,293 issued on Apr. 11, 1989 to Wagner Zipchange Inc. in which an opaque strip or partition is coupled to a lateral edge of a letter panel to abut and overlap an immediately adjacent panel.
Signs of this form are also often adapted to permit the rearranging of the letter panels such that, for example, a store may modify the sign to advertise different items or to change displayed prices. On the other hand, it is desirable that the signs are tamperproof and not readily modified or rearranged by unauthorized persons.
Signs of this form are generally of fairly large dimensions and thus are expensive to store and transport. Certain transport difficulties may be overcome by mounting the sign on a trailer, but this adds significantly to the cost of the sign and may facilitate theft of an unattended sign.